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Scientists stunned to find a blind fish that walks up walls

A fascinating discovery sheds light on our ancestors' transition from the ocean to solid ground.

A team of researchers from the New Jersey Institute of Technology has made a discovery that could help explain how our earliest ancestors first made the transition from living in the ocean to living on land. According to a report from CS Monitor, researchers working in Thailand have discovered a blind cavefish that moves like no other fish known to man.

Other fish have been observed “walking,” but Cryptotora thamicola is unlike any other previously described. The blind fish can walk on four limbs, and can even climb up moving waterfalls like a salamander. Unlike other fish species that have developed the ability to walk, this little one uses a method not seen since some of the earliest creatures emerged on dry land.

The walking cavefish had developed features like those found on other tetrapods, believed to have developed roughly 420 million years ago. Tetrapods were some of the first animals with the ability to walk on land. One of the major evolutionary shifts involved in this transition was the development of stiff spines created from interlocking vertebrae. The shift also marked the first time a pelvis appeared in the fossil record.

The blind cavefish still alive today bears many similarities to early tetrapods. According to study co-author Brooke Flammang, an ichthyologist from Harvard University’s Museum of Comparatie Zoology, “It possesses morphological features that have previously only been attributed to tetrapods. The pelvis and vertebral column of this fish allow it to support its body weight against gravity and provide large sites for muscle attachment for walking.”

The tiny fish’s pelvis enables it to wiggle from side to side, much like a salamander. The authors described the motion as a “standing wave” – one that allows the fish to scale seemingly impossible waterfalls with ease.

The cavefish was first described in 1985, but the recent study sheds new light on its morphology and how this enables it to walk. “This research gives us insight into the plasticity of the fish body plan and the convergent morphological features that were seen in the evolution of tetrapods,” explained Dr. Flammang.

A press release from the New Jersey Institute of Technology describing the details of the study can be found here.